EXISTENCE AND UNIQUENESS OF GLOBAL SOLUTION FOR CERTAIN NONLINEAR DEGENERATE PARABOLIC SYSTEMS

ＥＸＩＳＴＥＮＣＥＡＮＤＵＮＩＱＵＥＮＥＳＳＯＦＧＬＯＢＡＬＳＯＬＵＴＩＯＮＦＯＲＣＥＲＴＡＩＮＮＯＮＬＩＮＥＡＲＤＥＧＥＮＥＲＡＴＥＰＡＲＡＢＯＬＩＣ　ＳＹＳＴＥＭＳＬＵＧＵＯＦＵ（卢国富）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，Ｐｕｔｉ...     

ON THE STATISTICAL MECHANICS OF PROBABILISTIC MODELS OF NEURAL NETWORKS

ＯＮＴＨＥＳＴＡＴＩＳＴＩＣＡＬＭＥＣＨＡＮＩＣＳＯＦＰＲＯＢＡＢＩＬＩＳＴＩＣ　ＭＯＤＥＬＳＯＦＮＥＵＲＡＬＮＥＴＷＯＲＫＳＱＩＡＮＭＩＮＰＩＮＧ（钱敏平）（ＤｅｐａｒｔｍｅｎｔｏｆＰｒｏｂａｂｉｌｉｔｙａｎｄＳｔａｔｉｓｔｉｃｓ，ＢｅｉｊｉｎｇＵ...     

ASYMPTOTIC CANONICAL FORMS AND ITERATED LOGARITHM RATE RESULTS OF LEAST SQUARES ESTIMATES FOR UNSTABLE ARMA MODELS

ＡＳＹＭＰＴＯＴＩＣＣＡＮＯＮＩＣＡＬＦＯＲＭＳＡＮＤＩＴＥＲＡＴＥＤＬＯＧＡＲＩＴＨＭＲＡＴＥＲＥＳＵＬＴＳＯＦＬＥＡＳＴＳＱＵＡＲＥＳＥＳＴＩＭＡＴＥＳＦＯＲＵＮＳＴＡＢＬＥＡＲＭＡＭＯＤＥＬＳＺＨＡＮＧＨＵＭＩＮＧ（张虎明）（Ｄｅｐａｒｔｍｅｎ...     

ON EXISTENCE， UNIQUENESS AND REGULARITY OF STEADY STATE SOLUTIONS TO THE BASIC SEMICONDUCTOR EQUATIONS

ＯＮＥＸＩＳＴＥＮＣＥ，ＵＮＩＱＵＥＮＥＳＳＡＮＤＲＥＧＵＬＡＲＩＴＹＯＦＳＴＥＡＤＹＳＴＡＴＥＳＯＬＵＴＩＯＮＳＴＯＴＨＥＢＡＳＩＣＳＥＭＩＣＯＮＤＵＣＴＯＲＥＱＵＡＴＩＯＮＳＷａｎｇＹｕａｎｍｉｎｇ（王元明）ＦａｎＪｉｓｈａｎ（樊继山）（Ｄｅｐｔ...     

A NOTE FOR THE TOPOLOGICAL CLASSIFICATION OF STRUCTURALLY STABLE QUADRATIC DIFFERENTIAL SYSTEMS WITHOUT LIMIT CYCLES

ＡＮＯＴＥＦＯＲＴＨＥＴＯＰＯＬＯＧＩＣＡＬＣＬＡＳＳＩＦＩＣＡＴＩＯＮＯＦＳＴＲＵＣＴＵＲＡＬＬＹＳＴＡＢＬＥＱＵＡＤＲＡＴＩＣＤＩＦＦＥＲＥＮＴＩＡＬＳＹＳＴＥＭＳＷＩＴＨＯＵＴＬＩＭＩＴＣＹＣＬＥＳ￥ＹｅＷｅｉｙｉｎ（叶惟寅）（ＮａｎｊｉｎｇＮ...     

EXISTENCE OF GLOBAL SMOOTH SOLUTIONS FOR TWO IMPORTANT NONSTRICTLY QUASILINEAR HYPERBOLIC SYSTEMS

（朱长江）（赵会江）ＥＸＩＳＴＥＮＣＥＯＦＧＬＯＢＡＬＳＭＯＯＴＨＳＯＬＵＴＩＯＮＳＦＯＲＴＷＯＩＭＰＯＲＴＡＮＴＮＯＮＳＴＲＩＣＴＬＹＱＵＡＳＩＬＩＮＥＡＲＨＹＰＥＲＢＯＬＩＣＳＹＳＴＥＭＳ￥ＺｈｕＣｈａｎｇｊｉａｎｇ；ＺｈａｏＨｕｉｊａｎｇ（Ｗｕ...     

ESTIMATE FOR DISTANCE-COEFFICIENT OF MATRICES

ＥＳＴＩＭＡＴＥＦＯＲＤＩＳＴＡＮＣＥ┐ＣＯＥＦＦＩＣＩＥＮＴＯＦＭＡＴＲＩＣＥＳＬＵＦＡＮＧＹＡＮＡｂｓｔｒａｃｔ．ＭｏｔｉｖａｔｉｏｎｏｆｔｈｉｓｐａｐｅｒｉｓａｎｏｐｅｎｐｒｏｂｌｅｍｅｘｐｏｓｅｄｂｙＢ．Ｂｅａｕｚａｍｙ［１］．ＬｅｔＭｂｅａ...     

LOCAL TOPOLOGICAL STRUCTURE OF THE PLANE CUBIC SYSTEM IN THE UNDETERMINED SIGN CASE

（李学敏）（杨殿武）ＬＯＣＡＬＴＯＰＯＬＯＧＩＣＡＬＳＴＲＵＣＴＵＲＥＯＦＴＨＥＰＬＡＮＥＣＵＢＩＣＳＹＳＴＥＭＩＮＴＨＥＵＮＤＥＴＥＲＭＩＮＥＤＳＩＧＮＣＡＳＥ￥ＬｉＸｕｅｍｉｎ；ＹａｎｇＤｉａｎｗｕ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ...     

ALMOST PERIODIC SOLUTIONS OF LINEAR DIFFERENTIAL EQUATIONS WITH PIECEWISE CONSTANT ARGUMENT

ＡＬＭＯＳＴＰＥＲＩＯＤＩＣＳＯＬＵＴＩＯＮＳＯＦＬＩＮＥＡＲＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳＷＩＴＨＰＩＥＣＥＷＩＳＥＣＯＮＳＴＡＮＴＡＲＧＵＭＥＮＴＹＵＡＮＲＯＮＧＨＯＮＧＪＩＡＬＩＮＭａｎｕｓｃｒｉｐｔｒｅｃｅｉｖｅｄＪｕ...     

STABILITY OF SOLUTIONS OF GENERALIZED LOGISTIC DIFFERENCE EQUATIONS

ＳＴＡＢＩＬＩＴＹＯＦＳＯＬＵＴＩＯＮＳＯＦＧＥＮＥＲＡＬＩＺＥＤＬＯＧＩＳＴＩＣＤＩＦＦＥＲＥＮＣＥＥＱＵＡＴＩＯＮＳ￥ＷｉｌｌｉａｍＢｒｉｄｅｎａｎｄＺｈａｎｇＳｈｕｎｉａｎ（张书年）（ＵｕｎｉｖｅｒｓｉｔｙｏｆＲｈｏｄｅＩｓｌａｎｄ．Ｋｉｎｇｓ...     

Characterizations of absolute F σδ-sets

We give several internal characterizations for the metrizable absolute F -spaces. The characterizing conditions involve the existence of compatible bicomplete quasi-metrics, of complete sequences of -discrete closed covers and of compact -discrete closed networks.     

Generalizations of Perfect, Semiperfect, and Semiregular Rings

For a ring R and a right R-module M, a submodule N of M is said to be -small in M if, whenever N + X = M with M/X singular, we have X = M. If there exists an epimorphism p: P M such that P is projective and Ker(p) is -small in P, then we say that P is a projective -cover of M. A ring R is called -perfect (resp., -semiperfect, -semiregular) if every R-module (resp., simple R-module, cyclically presented R-module) has a projective -cover. The class of all -perfect (resp., -semiperfect, -semiregular) rings contains properly the class of all right perfect (resp., semiperfect, semiregular) rings. This paper is devoted to various properties and characterizations of -perfect, -semiperfect, and -semiregular rings. We define (R) by (R)/Soc(R_R) = Jac(R/Soc(R_R)) and show, among others, the following results:

D λ -cycles in 3-cyclable graphs

Letk and be positive integers, andG a 2-connected graph of ordern with minimum degree and independence number. A cycleC ofG is called aD -cycle if every component ofG – V(C) has order smaller than. The graphG isk-cyclable if anyk vertices ofG lie on a common cycle. A previous result of the author is that if k 2, G isk-connected and every connected subgraphH ofG of order has at leastn +k ² + 1/k + 1 – vertices outsideH adjacent to at least one vertex ofH, thenG contains aD -cycle. Here it is conjectured that k-connected can be replaced by k-cyclable, and this is proved fork = 3. As a consequence it is shown that ifn 4 – 6, or ifG is triangle-free andn 8 – 10, thenG contains aD ₃-cycle orG , where denotes a well-known class of nonhamiltonian graphs of connectivity 2. As an analogue of a result of Nash-Williams it follows that ifn 4 – 6 and – 1, thenG is hamiltonian orG . The results are all best possible and compare favorably with recent results on hamiltonicity of graphs which are close to claw-free.     

The lower algebraicK-theory of virtually infinite cyclic groups

This paper gives a proof of a conjecture of W.-C. Hsiang for the negativeK-theory of integral grouprings , when the group is a subgroup of a uniform lattice in a Lie group. The authors' earlier paper reduced this result to the very special cases where either is finite or is virtually infinite cyclic. The finite case was done much earlier by Carter extending results of Bass and Murthy. The major work of the present paper consists of proving the conjecture when is virtually infinite cyclic.Both authors were supported in part by the National Science Foundation.     

О метрических свойст вах особых множеств г оломорфных функций нескольких п еременных

LetG be a domain inC ⁿ ,EG, mes E=0 for (r)=r ^2n–1(r), where (r) is a nondecreasing non-negative function (r>0). Iff(z) is holomorphic inGE and (,f, GE)(), C=const, thenf(z) is holomorphic inG.The impossibility of the relaxation of the stipulations on () and(r) is also established.The statement above is a corollary to a more general result about the representation of a holomorphic function from a certain class in the form of an integral with respect to -measure, extended over the set of singular points of the function.     

On Piecewise-Constant Approximation of Continuous Functions of n Variables in Integral Metrics

We consider the approximation by piecewise-constant functions for classes of functions of many variables defined by moduli of continuity of the form (₁, ..., _n ) = ₁(₁) + ... + _n ( _n ), where _i ( _i ) are ordinary moduli of continuity that depend on one variable. In the case where _i ( _i ) are convex upward, we obtain exact error estimates in the following cases: (i) in the integral metric L ₂ for (₁, ..., _n ) = ₁(₁) + ... + _n ( _n ); (ii) in the integral metric L _p (p 1) for (₁, ..., _n ) = c ₁₁ + ... + c _{n n} ; (iii) in the integral metric L _{(2, ..., 2, 2r)} (r = 2, 3, ...) for (₁, ..., _n ) = ₁(₁) + ... + _{n – 1}( _{n – 1}) + c _{n n} .     

Some Properties of Isologism of Groups and Baer-Invariants

Let be a variety of groups defined by the set of laws V. In this paper we study the concept of -isologism of groups in terms of -extensions and their connections with the Baer-invariant of groups are also discussed.AMS Subject Classification (2000): primary 20F14, 20F19, secondary 20E10     

Piecewise Constant Roughly Convex Functions

This paper investigates some kinds of roughly convex functions, namely functions having one of the following properties: -convexity (in the sense of Klötzler and Hartwig), -convexity and midpoint -convexity (in the sense of Hu, Klee, and Larman), -convexity and midpoint -convexity (in the sense of Phu). Some weaker but equivalent conditions for these kinds of roughly convex functions are stated. In particular, piecewise constant functions satisfying f(x) = f([x]) are considered, where [x] denotes the integer part of the real number x. These functions appear in numerical calculation, when an original function g is replaced by f(x):=g([x]) because of discretization. In the present paper, we answer the question of when and in what sense such a function f is roughly convex.     

Aλδ-calculus with an algorithmicδ

In this paper we propose a system, based on-calculus, where the restriction of Church's to normal forms is dropped, while the monotony properties are weakened. The main feature of such a system is that the Church-Rosser property is maintained and all provable equalities between closed terms are semidecidable within it.     

Improvement of Bruck's completion theorem

Improving Bruck's Completion-Theorem for nets, we show that a net of order k and degree k + 1 – can be extended to an affine plane, if 3k > 8³ – 18² + 8 + 4. As applications we obtain the following two theorems: A maximal partial t-spread in PG(2t + 1, q), q not a square, with deficiency > 0 satisfies 8³ – 18² + 8 + 4 3q ². There exists an absolute constant c such that every linear space with constant point degree n + 1 and minimum line degree n + 1 – a can be embedded in a protective plane of order n provided that n > ca ³.